Integrated Circuit Including Gate Electrode Tracks Including Offset End-to-End Spacings

ABSTRACT

An integrated circuit includes a first gate electrode feature of a first gate electrode track that forms a first n-channel transistor as it crosses an n-diffusion region, and a second gate electrode feature of the first gate electrode track that forms a first p-channel transistor as it crosses a p-diffusion region. The first and second gate electrode features of the first gate electrode track are separated by a first end-to-end spacing. The integrated circuit includes a first gate electrode feature of a second gate electrode track that forms a second n-channel transistor as it crosses the n-diffusion region, and a second gate electrode feature of the second gate electrode track that forms a second p-channel transistor as it crosses the p-diffusion region. The first and second gate electrode features of the second gate electrode track are separated by a second end-to-end spacing that is offset from the first end-to-end spacing.

CLAIM OF PRIORITY

This application is a continuation application under 35 U.S.C. 120 ofprior U.S. application Ser. No. 12/572,225, filed Oct. 1, 2009, andentitled “Semiconductor Device with Gate Level Including Gate ElectrodeConductors for Transistors of First Type and Transistors of Second Typewith Some Gate Electrode Conductors of Different Length” (As Amended),which is a continuation application under 35 U.S.C. 120 of prior U.S.application Ser. No. 12/212,562, filed Sep. 17, 2008, entitled “DynamicArray Architecture,” and issued as U.S. Pat. No. 7,842,975, which is acontinuation application under 35 U.S.C. 120 of prior U.S. applicationSer. No. 11/683,402, filed Mar. 7, 2007, entitled “Dynamic ArrayArchitecture,” and issued as U.S. Pat. No. 7,446,352, which claimspriority under 35 U.S.C. 119(e) to U.S. Provisional Patent ApplicationNo. 60/781,288, filed Mar. 9, 2006. Each of the above-identifiedapplications is incorporated herein by reference in its entirety.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is related to each application identified in the tablebelow. The disclosure of each application identified in the table belowis incorporated herein by reference in its entirety.

Attorney Docket No. Application No. Filing Date TELAP004AC2 12/561,207Sep. 16, 2009 TELAP004AC3 12/561,216 Sep. 16, 2009 TELAP004AC412/561,220 Sep. 16, 2009 TELAP004AC5 12/561,224 Sep. 16, 2009TELAP004AC6 12/561,229 Sep. 16, 2009 TELAP004AC7 12/561,234 Sep. 16,2009 TELAP004AC8 12/561,238 Sep. 16, 2009 TELAP004AC9 12/561,243 Sep.16, 2009 TELAP004AC10 12/561,246 Sep. 16, 2009 TELAP004AC11 12/561,247Sep. 16, 2009 TELAP004AC12 12/563,031 Sep. 18, 2009 TELAP004AC1312/563,042 Sep. 18, 2009 TELAP004AC14 12/563,051 Sep. 18, 2009TELAP004AC15 12/563,056 Sep. 18, 2009 TELAP004AC16 12/563,061 Sep. 18,2009 TELAP004AC17 12/563,063 Sep. 18, 2009 TELAP004AC18 12/563,066 Sep.18, 2009 TELAP004AC19 12/563,074 Sep. 18, 2009 TELAP004AC20 12/563,076Sep. 18, 2009 TELAP004AC21 12/563,077 Sep. 18, 2009 TELAP004AC2212/567,528 Sep. 25, 2009 TELAP004AC23 12/567,542 Sep. 25, 2009TELAP004AC24 12/567,555 Sep. 25, 2009 TELAP004AC25 12/567,565 Sep. 25,2009 TELAP004AC26 12/567,574 Sep. 25, 2009 TELAP004AC27 12/567,586 Sep.25, 2009 TELAP004AC28 12/567,597 Sep. 25, 2009 TELAP004AC29 12/567,602Sep. 25, 2009 TELAP004AC30 12/567,609 Sep. 25, 2009 TELAP004AC3112/567,616 Sep. 25, 2009 TELAP004AC32 12/567,623 Sep. 25, 2009TELAP004AC33 12/567,630 Sep. 25, 2009 TELAP004AC34 12/567,634 Sep. 25,2009 TELAP004AC35 12/567,641 Sep. 25, 2009 TELAP004AC36 12/567,648 Sep.25, 2009 TELAP004AC37 12/567,654 Sep. 25, 2009 TELAP004AC38 12/571,343Sep. 30, 2009 TELAP004AC39 12/571,351 Sep. 30, 2009 TELAP004AC4012/571,357 Sep. 30, 2009 TELAP004AC41 12/571,998 Oct. 1, 2009TELAP004AC42 12/572,011 Oct. 1, 2009 TELAP004AC43 12/572,022 Oct. 1,2009 TELAP004AC44 12/572,046 Oct. 1, 2009 TELAP004AC45 12/572,055 Oct.1, 2009 TELAP004AC46 12/572,061 Oct. 1, 2009 TELAP004AC47 12/572,068Oct. 1, 2009 TELAP004AC48 12/572,077 Oct. 1, 2009 TELAP004AC4912/572,091 Oct. 1, 2009 TELAP004AC50 12/572,194 Oct. 1, 2009TELAP004AC51 12/572,201 Oct. 1, 2009 TELAP004AC52 12/572,212 Oct. 1,2009 TELAP004AC53 12/572,218 Oct. 1, 2009 TELAP004AC54 12/572,221 Oct.1, 2009 TELAP004AC55 12/572,225 Oct. 1, 2009 TELAP004AC56 12/572,228Oct. 1, 2009 TELAP004AC57 12/572,229 Oct. 1, 2009 TELAP004AC5812/572,232 Oct. 1, 2009 TELAP004AC59 12/572,237 Oct. 1, 2009TELAP004AC60 12/572,239 Oct. 1, 2009 TELAP004AC61 12/572,243 Oct. 1,2009 BECKP004B 12/013,342 Jan. 11, 2008 BECKP004B.C1 13/073,994 Mar. 28,2011 BECKP004C 12/013,356 Jan. 11, 2008 BECKP004C.C1 13/047,474 Mar. 14,2011 BECKP004D 12/013,366 Jan. 11, 2008 BECKP004D.C1 13/007,582 Jan. 14,2011 BECKP004D.C2 13/007,584 Jan. 14, 2011 TELAP014 12/363,705 Jan. 30,2009 TELAP015A 12/402,465 Mar. 11, 2009 TELAP015AC1 12/753,711 Apr. 2,2010 TELAP015AC2 12/753,727 Apr. 2, 2010 TELAP015AC3 12/753,733 Apr. 2,2010 TELAP015AC4 12/753,740 Apr. 2, 2010 TELAP015AC5 12/753,753 Apr. 2,2010 TELAP015AC6 12/753,758 Apr. 2, 2010 TELAP015AC6A 13/741,298 Jan.14, 2013 TELAP015AC7 12/753,766 Apr. 2, 2010 TELAP015AC7A 13/589,028Aug. 17, 2012 TELAP015AC8 12/753,776 Apr. 2, 2010 TELAP015 AC912/753,789 Apr. 2, 2010 TELAP015AC10 12/753,793 Apr. 2, 2010TELAP015AC11 12/753,795 Apr. 2, 2010 TELAP015AC12 12/753,798 Apr. 2,2010 TELAP015AC12A 13/741,305 Jan. 14, 2013 TELAP015AC13 12/753,805 Apr.2, 2010 TELAP015AC14 12/753,810 Apr. 2, 2010 TELAP015AC15 12/753,817Apr. 2, 2010 TELAP015AC16 12/754,050 Apr. 5, 2010 TELAP015AC1712/754,061 Apr. 5, 2010 TELAP015AC18 12/754,078 Apr. 5, 2010TELAP015AC19 12/754,091 Apr. 5, 2010 TELAP015AC20 12/754,103 Apr. 5,2010 TELAP015AC21 12/754,114 Apr. 5, 2010 TELAP015AC22 12/754,129 Apr.5, 2010 TELAP015AC23 12/754,147 Apr. 5, 2010 TELAP015AC24 12/754,168Apr. 5, 2010 TELAP015AC25 12/754,215 Apr. 5, 2010 TELAP015AC2612/754,233 Apr. 5, 2010 TELAP015AC27 12/754,351 Apr. 5, 2010TELAP015AC27A 13/591,141 Aug. 21, 2012 TELAP015AC28 12/754,384 Apr. 5,2010 TELAP015AC29 12/754,563 Apr. 5, 2010 TELAP015AC30 12/754,566 Apr.5, 2010 TELAP016 12/399,948 Mar. 7, 2009 TELAP017 12/411,249 Mar. 25,2009 TELAP017.D 13/085,447 Apr. 12, 2011 TELAP018 12/484,130 Jun. 12,2009 TELAP019 12/479,674 Jun. 5, 2009 TELAP020 12/481,445 Jun. 9, 2009TELAP021 12/497,052 Jul. 2, 2009 TELAP021C1 13/540,529 Jul. 2, 2012TELAP022A 12/466,335 May 14, 2009 TELAP022B 12/466,341 May 14, 2009TELAP023 12/512,932 Jul. 30, 2009 TELAP048 12/435,672 May 5, 2009TELAP049 12/775,429 May 6, 2010 TELAP051 12/904,134 Oct. 13, 2010TELAP053 13/373,470 Nov. 14, 2011 TELAP054 13/312,673 Dec. 6, 2011TELAP055 13/473,439 May 16, 2012 TELAP056 13/740,191 Jan. 12, 2013

BACKGROUND

A push for higher performance and smaller die size drives thesemiconductor industry to reduce circuit chip area by approximately 50%every two years. The chip area reduction provides an economic benefitfor migrating to newer technologies. The 50% chip area reduction isachieved by reducing the feature sizes between 25% and 30%. Thereduction in feature size is enabled by improvements in manufacturingequipment and materials. For example, improvement in the lithographicprocess has enabled smaller feature sizes to be achieved, whileimprovement in chemical mechanical polishing (CMP) has in-part enabled ahigher number of interconnect layers.

In the evolution of lithography, as the minimum feature size approachedthe wavelength of the light source used to expose the feature shapes,unintended interactions occurred between neighboring features. Todayminimum feature sizes are approaching 45 nm (nanometers), while thewavelength of the light source used in the photolithography processremains at 193 nm. The difference between the minimum feature size andthe wavelength of light used in the photolithography process is definedas the lithographic gap. As the lithographic gap grows, the resolutioncapability of the lithographic process decreases.

An interference pattern occurs as each shape on the mask interacts withthe light. The interference patterns from neighboring shapes can createconstructive or destructive interference. In the case of constructiveinterference, unwanted shapes may be inadvertently created. In the caseof destructive interference, desired shapes may be inadvertentlyremoved. In either case, a particular shape is printed in a differentmanner than intended, possibly causing a device failure. Correctionmethodologies, such as optical proximity correction (OPC), attempt topredict the impact from neighboring shapes and modify the mask such thatthe printed shape is fabricated as desired. The quality of the lightinteraction prediction is declining as process geometries shrink and asthe light interactions become more complex.

In view of the foregoing, a solution is needed for managing lithographicgap issues as technology continues to progress toward smallersemiconductor device features sizes.

SUMMARY

In one embodiment, an integrated circuit is disclosed to include a firstgate electrode feature of a first gate electrode track. The first gateelectrode feature of the first gate electrode track forms a firstn-channel transistor as it crosses an n-diffusion region. The integratedcircuit also includes a second gate electrode feature of the first gateelectrode track. The second gate electrode feature of the first gateelectrode track forms a first p-channel transistor as it crosses ap-diffusion region. The first and second gate electrode features of thefirst gate electrode track are separated by a first end-to-end spacing.The integrated circuit also includes a first gate electrode feature of asecond gate electrode track. The first gate electrode feature of thesecond gate electrode track forms a second n-channel transistor as itcrosses the n-diffusion region. The integrated circuit also includes asecond gate electrode feature of the second gate electrode track. Thesecond gate electrode feature of the second gate electrode track forms asecond p-channel transistor as it crosses the p-diffusion region. Thefirst and second gate electrode features of the second gate electrodetrack are separated by a second end-to-end spacing that is offset fromthe first end-to-end spacing such that a line of sight perpendicular tothe first and second gate electrode tracks does not exist through thefirst and second end-to-end spacings.

In another embodiment, a cell of a semiconductor device is disclosed.The cell includes a substrate portion formed to include a plurality ofdiffusion regions. The plurality of diffusion regions respectivelycorrespond to active areas of the substrate portion within which one ormore processes are applied to modify one or more electricalcharacteristics of the active areas of the substrate portion. Theplurality of diffusion regions are separated from each other by one ormore non-active regions of the substrate portion.

Also in this embodiment, the cell includes a gate electrode level of thecell formed above the substrate portion. The gate electrode levelincludes a number of conductive features defined to extend in only afirst parallel direction. Adjacent ones of the number of conductivefeatures that share a common line of extent in the first paralleldirection are fabricated from respective originating layout featuresthat are separated from each other by an end-to-end spacing having asize measured in the first parallel direction. The size of eachend-to-end spacing between originating layout features corresponding toadjacent ones of the number of conductive features within the gateelectrode level of the cell is substantially equal and is minimized toan extent allowed by a semiconductor device manufacturing capability.The number of conductive features within the gate electrode level of thecell includes conductive features defined along at least four differentvirtual lines of extent in the first parallel direction across the gateelectrode level of the cell.

A width size of the conductive features within the gate electrode levelis measured perpendicular to the first parallel direction. The widthsize of the conductive features within a photolithographic interactionradius within the gate electrode level is less than a wavelength oflight used in a photolithography process to fabricate the conductivefeatures within the gate electrode level. The wavelength of light usedin the photolithography process is less than or equal to 193 nanometers.The photolithographic interaction radius is five wavelengths of lightused in the photolithography process.

Some of the number of conductive features within the gate electrodelevel of the cell are defined to include one or more gate electrodeportions which extend over one or more of the active areas of thesubstrate portion corresponding to the plurality of diffusion regions.Each gate electrode portion and a corresponding active area of thesubstrate portion over which it extends together define a respectivetransistor device.

Also in this embodiment, the cell includes a number of interconnectlevels formed above the gate electrode level of the cell. The substrateportion, the gate electrode level of the cell, and the number ofinterconnect levels are spatially aligned such that structuresfabricated within each of the substrate portion, the gate electrodelevel of the cell, and the number of interconnect levels spatiallyrelate to connect as required to form functional electronic deviceswithin the semiconductor device.

Other aspects and advantages of the invention will become more apparentfrom the following detailed description, taken in conjunction with theaccompanying drawings, illustrating by way of example the presentinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustration showing a number of neighboring layoutfeatures and a representation of light intensity used to render each ofthe layout features, in accordance with one embodiment of the presentinvention;

FIG. 2 is an illustration showing a generalized stack of layers used todefine a dynamic array architecture, in accordance with one embodimentof the present invention;

FIG. 3A is an illustration showing an exemplary base grid to beprojected onto the dynamic array to facilitate definition of therestricted topology, in accordance with one embodiment of the presentinvention;

FIG. 3B is an illustration showing separate base grids projected acrossseparate regions of the die, in accordance with an exemplary embodimentof the present invention;

FIG. 3C is an illustration showing an exemplary linear-shaped featuredefined to be compatible with the dynamic array, in accordance with oneembodiment of the present invention;

FIG. 3D is an illustration showing another exemplary linear-shapedfeature defined to be compatible with the dynamic array, in accordancewith one embodiment of the present invention;

FIG. 4 is an illustration showing a diffusion layer layout of anexemplary dynamic array, in accordance with one embodiment of thepresent invention;

FIG. 5 is an illustration showing a gate electrode layer and a diffusioncontact layer above and adjacent to the diffusion layer of FIG. 4, inaccordance with one embodiment of the present invention;

FIG. 6 is an illustration showing a gate electrode contact layer definedabove and adjacent to the gate electrode layer of FIG. 5, in accordancewith one embodiment of the present invention;

FIG. 7A is an illustration showing a traditional approach for makingcontact to the gate electrode;

FIG. 7B is an illustration showing a gate electrode contact defined inaccordance with one embodiment of the present invention;

FIG. 5A is an illustration showing a metal 1 layer defined above andadjacent to the gate electrode contact layer of FIG. 6, in accordancewith one embodiment of the present invention;

FIG. 8B is an illustration showing the metal 1 layer of FIG. 5A withlarger track widths for the metal 1 ground and power tracks, relative tothe other metal 1 tracks;

FIG. 9 is an illustration showing a via 1 layer defined above andadjacent to the metal 1 layer of FIG. 5A, in accordance with oneembodiment of the present invention;

FIG. 10 is an illustration showing a metal 2 layer defined above andadjacent to the via 1 layer of FIG. 9, in accordance with one embodimentof the present invention;

FIG. 11 is an illustration showing conductor tracks traversing thedynamic array in a first diagonal direction relative to the first andsecond reference directions (x) and (y), in accordance with oneembodiment of the present invention;

FIG. 12 is an illustration showing conductor tracks traversing thedynamic array in a second diagonal direction relative to the first andsecond reference directions (x) and (y), in accordance with oneembodiment of the present invention;

FIG. 13A is an illustration showing an example of a sub-resolutioncontact layout used to lithographically reinforce diffusion contacts andgate electrode contacts, in accordance with one embodiment of thepresent invention;

FIG. 13B is an illustration showing the sub-resolution contact layout ofFIG. 13A with sub-resolution contacts defined to fill the grid to theextent possible, in accordance with one embodiment of the presentinvention;

FIG. 13C is an illustration showing an example of a sub-resolutioncontact layout utilizing various shaped sub-resolution contacts, inaccordance with one embodiment of the present invention;

FIG. 13D is an illustration showing an exemplary implementation ofalternate phase shift masking (APSM) with sub-resolution contacts, inaccordance with one embodiment of the present invention; and

FIG. 14 is an illustration showing a semiconductor chip structure, inaccordance with one embodiment of the present invention.

FIG. 15 shows an example layout architecture defined in accordance withone embodiment of the present invention.

DETAILED DESCRIPTION

In the following description, numerous specific details are set forth inorder to provide a thorough understanding of the present invention. Itwill be apparent, however, to one skilled in the art that the presentinvention may be practiced without some or all of these specificdetails. In other instances, well known process operations have not beendescribed in detail in order not to unnecessarily obscure the presentinvention.

Generally speaking, a dynamic array architecture is provided to addresssemiconductor manufacturing process variability associated with acontinually increasing lithographic gap. In the area of semiconductormanufacturing, lithographic gap is defined as the difference between theminimum size of a feature to be defined and the wavelength of light usedto render the feature in the lithographic process, wherein the featuresize is less than the wavelength of the light. Current lithographicprocesses utilize a light wavelength of 193 nm. However, current featuresizes are as small as 65 nm and are expected to soon approach sizes assmall as 45 nm. With a size of 65 nm, the shapes are three times smallerthan the wavelength of the light used to define the shapes. Also,considering that the interaction radius of light is about five lightwavelengths, it should be appreciated that shapes exposed with a 193 nmlight source will influence the exposure of shapes approximately 5*193nm (965 nm) away. When considering the 65 nm sized features with respectto 90 nmm sized features, it should be appreciated that approximatelytwo times as many 65 nm sizes features may be within the 965 nminteraction radius of the 193 nm light source as compared to the 90 nmsized features.

Due to the increased number of features within the interaction radius ofthe light source, the extent and complexity of light interferencecontributing to exposure of a given feature is significant.Additionally, the particular shapes associated with the features withinthe interaction radius of the light source weighs heavily on the type oflight interactions that occur. Traditionally, designers were allowed todefine essentially any two-dimensional topology of feature shapes solong as a set of design rules were satisfied. For example, in a givenlayer of the chip, i.e., in a given mask, the designer may have definedtwo-dimensionally varying features having bends that wrap around eachother. When such two-dimensionally varying features are located inneighboring proximity to each other, the light used to expose thefeatures will interact in a complex and generally unpredictable manner.The light interaction becomes increasingly more complex andunpredictable as the feature sizes and relative spacing become smaller.

Traditionally, if a designer follows the established set of designrules, the resulting product will be manufacturable with a specifiedprobability associated with the set of design rules. Otherwise, for adesign that violates the set of design rules, the probability ofsuccessful manufacture of the resulting product is unknown. To addressthe complex light interaction between neighboring two-dimensionallyvarying features, in the interest of successful product manufacturing,the set of design rules is expanded significantly to adequately addressthe possible combinations of two-dimensionally varying features. Thisexpanded set of design rules quickly becomes so complicated and unwieldythat application of the expanded set of design rules becomesprohibitively time consuming, expensive, and prone to error. Forexample, the expanded set of design rules requires complex verification.Also, the expanded set of design rules may not be universally applied.Furthermore, manufacturing yield is not guaranteed even if all designrules are satisfied.

It should be appreciated that accurate prediction of all possible lightinteractions when rendering arbitrarily-shaped two-dimensional featuresis generally not feasible. Moreover, as an alternative to or incombination with expansion of the set of design rules, the set of designrules may also be modified to include increased margin to account forunpredictable light interaction between the neighboringtwo-dimensionally varying features. Because the design rules areestablished in an attempt to cover the random two-dimensional featuretopology, the design rules may incorporate a significant amount ofmargin. While addition of margin in the set of design rules assists withthe layout portions that include the neighboring two-dimensionallyvarying features, such global addition of margin causes other portionsof the layout that do not include the neighboring two-dimensionallyvarying features to be overdesigned, thus leading to decreasedoptimization of chip area utilization and electrical performance.

In view of the foregoing, it should be appreciated that semiconductorproduct yield is reduced as a result of parametric failures that stemfrom variability introduced by design-dependent unconstrained featuretopologies, i.e., arbitrary two-dimensionally varying features disposedin proximity to each other. By way of example, these parametric failuresmay result from failure to accurately print contacts and vias and fromvariability in fabrication processes. The variability in fabricationprocesses may include CMP dishing, layout feature shape distortion dueto photolithography, gate distortion, oxide thickness variability,implant variability, and other fabrication related phenomena. Thedynamic array architecture of the present invention is defined toaddress the above-mentioned semiconductor manufacturing processvariability.

FIG. 1 is an illustration showing a number of neighboring layoutfeatures and a representation of light intensity used to render each ofthe layout features, in accordance with one embodiment of the presentinvention. Specifically, three neighboring linear-shaped layout features(101A-101C) are depicted as being disposed in a substantially parallelrelationship within a given mask layer. The distribution of lightintensity from a layout feature shape is represented by a sine function.The sine functions (103A-103C) represent the distribution of lightintensity from each of the layout features (101A-101C, respectively).The neighboring linear-shaped layout features (101A-101C) are spacedapart at locations corresponding to peaks of the sine functions(103A-103C). Thus, constructive interference between the light energyassociated with the neighboring layout features (101A-101C), i.e., atthe peaks of the sine functions (103A-103C), serves to reinforce theexposure of the neighboring shapes (101A-101C) for the layout featurespacing illustrated. In accordance with the foregoing, the lightinteraction represented in FIG. 1 represents a synchronous case.

As illustrated in FIG. 1, when linear-shaped layout features are definedin a regular repeating pattern at an appropriate spacing, constructiveinterference of the light energy associated with the various layoutfeatures serves to enhance the exposure of each layout feature. Theenhanced exposure of the layout features provided by the constructivelight interference can dramatically reduce or even eliminate a need toutilize optical proximity correction (OFC) and/or reticle enhancementtechnology (RET) to obtain sufficient rendering of the layout features.

A forbidden pitch, i.e., forbidden layout feature spacing, occurs whenthe neighboring layout features (101A-101C) are spaced such that peaksof the sine function associated with one layout feature align withvalleys of the sine function associated with another layout feature,thus causing destructive interference of the light energy. Thedestructive interference of the light energy causes the light energyfocused at a given location to be reduced. Therefore, to realize thebeneficial constructive light interference associated with neighboringlayout features, it is necessary to predict the layout feature spacingat which the constructive overlap of the sine function peaks will occur.Predictable constructive overlap of the sine function peaks andcorresponding layout feature shape enhancement can be realized if thelayout feature shapes are rectangular, near the same size, and areoriented in the same direction, as illustrated by the layout features(101A-101C) in FIG. 1. In this manner, resonant light energy fromneighboring layout feature shapes is used to enhance the exposure of aparticular layout feature shape.

FIG. 2 is an illustration showing a generalized stack of layers used todefine a dynamic array architecture, in accordance with one embodimentof the present invention. It should be appreciated that the generalizedstack of layers used to define the dynamic array architecture, asdescribed with respect to FIG. 2, is not intended to represent anexhaustive description of the CMOS manufacturing process. However, thedynamic array is to be built in accordance with standard CMOSmanufacturing processes. Generally speaking, the dynamic arrayarchitecture includes both the definition of the underlying structure ofthe dynamic array and the techniques for assembling the dynamic arrayfor optimization of area utilization and manufacturability. Thus, thedynamic array is designed to optimize semiconductor manufacturingcapabilities.

With regard to the definition of the underlying structure of the dynamicarray, the dynamic array is built-up in a layered manner upon a basesubstrate 201, e.g., upon a silicon substrate, or silicon-on-insulator(SOI) substrate. Diffusion regions 203 are defined in the base substrate201. The diffusion regions 203 represent selected regions of the basesubstrate 201 within which impurities are introduced for the purpose ofmodifying the electrical properties of the base substrate 201. Above thediffusion regions 203, diffusion contacts 205 are defined to enableconnection between the diffusion regions 203 and conductor lines. Forexample, the diffusion contacts 205 are defined to enable connectionbetween source and drain diffusion regions 203 and their respectiveconductor nets. Also, gate electrode features 207 are defined above thediffusion regions 203 to form transistor gates. Gate electrode contacts209 are defined to enable connection between the gate electrode features207 and conductor lines. For example, the gate electrode contacts 209are defined to enable connection between transistor gates and theirrespective conductor nets.

Interconnect layers are defined above the diffusion contact 205 layerand the gate electrode contact layer 209. The interconnect layersinclude a first metal (metal 1) layer 211, a first via (via 1) layer213, a second metal (metal 2) layer 215, a second via (via 2) layer 217,a third metal (metal 3) layer 219, a third via (via 3) layer 221, and afourth metal (metal 4) layer 223. The metal and via layers enabledefinition of the desired circuit connectivity. For example, the metaland via layers enable electrical connection of the various diffusioncontacts 205 and gate electrode contacts 209 such that the logicfunction of the circuitry is realized. It should be appreciated that thedynamic array architecture is not limited to a specific number ofinterconnect layers, i.e., metal and via layers. In one embodiment, thedynamic array may include additional interconnect layers 225, beyond thefourth metal (metal 4) layer 223. Alternatively, in another embodiment,the dynamic array may include less than four metal layers.

The dynamic array is defined such that layers (other than the diffusionregion layer 203) are restricted with regard to layout feature shapesthat can be defined therein. Specifically, in each layer other than thediffusion region layer 203, only linear-shaped layout features areallowed. A linear-shaped layout feature in a given layer ischaracterized as having a consistent vertical cross-section shape andextending in a single direction over the substrate. Thus, thelinear-shaped layout features define structures that areone-dimensionally varying. The diffusion regions 203 are not required tobe one-dimensionally varying, although they are allowed to be ifnecessary. Specifically, the diffusion regions 203 within the substratecan be defined to have any two-dimensionally varying shape with respectto a plane coincident with a top surface of the substrate. In oneembodiment, the number of diffusion bend topologies is limited such thatthe interaction between the bend in diffusion and the conductivematerial, e.g., polysilicon, that forms the gate electrode of thetransistor is predictable and can be accurately modeled. Thelinear-shaped layout features in a given layer are positioned to beparallel with respect to each other. Thus, the linear-shaped layoutfeatures in a given layer extend in a common direction over thesubstrate and parallel with the substrate.

The underlying layout methodology of the dynamic array uses constructivelight interference of light waves in the lithographic process toreinforce exposure of neighboring shapes in a given layer. Therefore,the spacing of the parallel, linear-shaped layout features in a givenlayer is designed around the constructive light interference of thestanding light waves such that lithographic correction (e.g., OPC/RET)is minimized or eliminated. Thus, in contrast to conventionalOPC/RET-based lithographic processes, the dynamic array defined hereinexploits the light interaction between neighboring features, rather thanattempting to compensate for the light interaction between neighboringfeatures.

Because the standing light wave for a given linear-shaped layout featurecan be accurately modeled, it is possible to predict how the standinglight waves associated with the neighboring linear-shaped layoutfeatures disposed in parallel in a given layer will interact. Therefore,it is possible to predict how the standing light wave used to expose onelinear-shaped feature will contribute to the exposure of its neighboringlinear-shaped features. Prediction of the light interaction betweenneighboring linear-shaped features enables the identification of anoptimum feature-to-feature spacing such that light used to render agiven shape will reinforce its neighboring shapes. Thefeature-to-feature spacing in a given layer is defined as the featurepitch, wherein the pitch is the center-to-center separation distancebetween adjacent linear-shaped features in a given layer.

To provide the desired exposure reinforcement between neighboringfeatures, the linear-shaped layout features in a given layer are spacedsuch that constructive and destructive interference of the light fromneighboring features will be optimized to produce the best rendering ofall features in the neighborhood. The feature-to-feature spacing in agiven layer is proportional to the wavelength of the light used toexpose the features. The light used to expose each feature within abouta five light wavelength distance from a given feature will serve toenhance the exposure of the given feature to some extent. Theexploitation of constructive interference of the standing light wavesused to expose neighboring features enables the manufacturing equipmentcapability to be maximized and not be limited by concerns regardinglight interactions during the lithography process.

As discussed above, the dynamic array incorporates a restricted topologyin which the features within each layer (other than diffusion) arerequired to be linear-shaped features that are oriented in a parallelmanner to traverse over the substrate in a common direction. With therestricted topology of the dynamic array, the light interaction in thephotolithography process can be optimized such that the printed image onthe mask is essentially identical to the drawn shape in the layout,i.e., essentially a 100% accurate transfer of the layout onto the resistis achieved.

FIG. 3A is an illustration showing an exemplary base grid to beprojected onto the dynamic array to facilitate definition of therestricted topology, in accordance with one embodiment of the presentinvention. The base grid can be used to facilitate parallel placement ofthe linear-shaped features in each layer of the dynamic array at theappropriate optimized pitch. Although not physically defined as part ofthe dynamic array, the base grid can be considered as a projection oneach layer of the dynamic array. Also, it should be understood that thebase grid is projected in a substantially consistent manner with respectto position on each layer of the dynamic array, thus facilitatingaccurate feature stacking and alignment.

In the exemplary embodiment of FIG. 3A, the base grid is defined as arectangular grid, i.e., Cartesian grid, in accordance with a firstreference direction (x) and a second reference direction (y). Thegridpoint-to-gridpoint spacing in the first and second referencedirections can be defined as necessary to enable definition of thelinear-shaped features at the optimized feature-to-feature spacing.Also, the gridpoint spacing in the first reference direction (x) can bedifferent than the gridpoint spacing in the second reference direction(y). In one embodiment, a single base grid is projected across theentire die to enable location of the various linear-shaped features ineach layer across the entire die. However, in other embodiments,separate base grids can be projected across separate regions of the dieto support different feature-to-feature spacing requirements within theseparate regions of the die. FIG. 3B is an illustration showing separatebase grids projected across separate regions of the die, in accordancewith an exemplary embodiment of the present invention.

The base grid is defined with consideration for the light interactionfunction, i.e., the sine function, and the manufacturing capability,wherein the manufacturing capability is defined by the manufacturingequipment and processes to be utilized in fabricating the dynamic array.With regard to the light interaction function, the base grid is definedsuch that the spacing between gridpoints enables alignment of peaks inthe sine functions describing the light energy projected uponneighboring gridpoints. Therefore, linear-shaped features optimized forlithographic reinforcement can be specified by drawing a line from afirst gridpoint to a second gridpoint, wherein the line represents arectangular structure of a given width. It should be appreciated thatthe various linear-shaped features in each layer can be specifiedaccording to their endpoint locations on the base grid and their width.

FIG. 3C is an illustration showing an exemplary linear-shaped feature301 defined to be compatible with the dynamic array, in accordance withone embodiment of the present invention. The linear-shaped feature 301has a substantially rectangular cross-section defined by a width 303 anda height 307. The linear-shaped feature 301 extends in a lineardirection to a length 305. In one embodiment, a cross-section of thelinear-shaped feature, as defined by its width 303 and height 307, issubstantially uniform along its length 305. It should be understood,however, that lithographic effects may cause a rounding of the ends ofthe linear-shaped feature 301. The first and second reference directions(x) and (y), respectively, of FIG. 3A are shown to illustrate anexemplary orientation of the linear-shaped feature on the dynamic array.It should be appreciated that the linear-shaped feature may be orientedto have its length 305 extend in either the first reference direction(x), the second reference direction (y), or in diagonal directiondefined relative to the first and second reference directions (x) and(y). Regardless of the linear-shaped features' particular orientationwith respect to the first and second reference directions (x) and (y),it should be understood that the linear-shaped feature is defined in aplane that is substantially parallel to a top surface of the substrateupon which the dynamic array is built. Also, it should be understoodthat the linear-shaped feature is free of bends, i.e., change indirection, in the plane defined by the first and second referencedirections.

FIG. 3D is an illustration showing another exemplary linear-shapedfeature 317 defined to be compatible with the dynamic array, inaccordance with one embodiment of the present invention. Thelinear-shaped feature 317 has a trapezoidal cross-section defined by alower width 313, an upper width 315, and a height 309. The linear-shapedfeature 317 extends in a linear direction to a length 311. In oneembodiment, the cross-section of the linear-shaped feature 317 issubstantially uniform along its length 311. It should be understood,however, that lithographic effects may cause a rounding of the ends ofthe linear-shaped feature 317. The first and second reference directions(x) and (y), respectively, of FIG. 3A are shown to illustrate anexemplary orientation of the linear-shaped feature on the dynamic array.It should be appreciated that the linear-shaped feature 317 may beoriented to have its length 311 extend in either the first referencedirection (x), the second reference direction (y), or in diagonaldirection defined relative to the first and second reference directions(x) and (y). Regardless of the particular orientation of thelinear-shaped feature 317 with regard to the first and second referencedirections (x) and (y), it should be understood that the linear-shapedfeature 317 is defined in a plane that is substantially parallel to atop surface of the substrate upon which the dynamic array is built.Also, it should be understood that the linear-shaped feature 317 is freeof bends, i.e., change in direction, in the plane defined by the firstand second reference directions.

Although FIGS. 3C and 3D explicitly discuss linear shaped featureshaving rectangular and trapezoidal cross-sections, respectively, itshould be understood that the linear shaped features having other typesof cross-sections can be defined within the dynamic array. Therefore,essentially any suitable cross-sectional shape of the linear-shapedfeature can be utilized so long as the linear-shaped feature is definedto have a length that extends in one direction, and is oriented to haveits length extend in either the first reference direction (x), thesecond reference direction (y), or in diagonal direction definedrelative to the first and second reference directions (x) and (y).

The layout architecture of the dynamic array follows the base gridpattern. Thus, it is possible to use grid points to represent wherechanges in direction occur in diffusion, wherein gate electrode andmetal linear-shaped features are placed, where contacts are placed,where opens are in the linear-shaped gate electrode and metal features,etc. The pitch of the gridpoints, i.e., the gridpoint-to-gridpointspacing, should be set for a given feature line width, e.g., width 303in FIG. 3C, such that exposure of neighboring linear-shaped features ofthe given feature line width will reinforce each other, wherein thelinear-shaped features are centered on gridpoints. With reference to thedynamic array stack of FIG. 2 and the exemplary base grid of FIG. 3A, inone embodiment, the gridpoint spacing in the first reference direction(x) is set by the required gate electrode gate pitch. In this sameembodiment, the gridpoint pitch in the second reference direction (y) isset by the metal 1 and metal 3 pitch. For example, in a 90 nm processtechnology, i.e., minimum feature size equal to 90 nm, the gridpointpitch in the second reference direction (y) is about 0.24 micron. In oneembodiment, metal 1 and metal 2 layers will have a common spacing andpitch. A different spacing and pitch may be used above the metal 2layer.

The various layers of the dynamic array are defined such that thelinear-shaped features in adjacent layers extend in a crosswise mannerwith respect to each other. For example, the linear-shaped features ofadjacent layers may extend orthogonally, i.e., perpendicularly withrespect to each other. Also, the linear-shaped features of one layer mayextend across the linear-shaped features of an adjacent layer at anangle, e.g., at about 45 degrees. For example, in one embodiment thelinear-shaped feature of one layer extend in the first referencedirection (x) and the linear-shaped features of the adjacent layerextend diagonally with respect to the first (x) and second (y) referencedirections. It should be appreciated that to route a design in thedynamic array having the linear-shaped features positioned in thecrosswise manner in adjacent layers, opens can be defined in thelinear-shaped features, and contacts and vias can be defined asnecessary.

The dynamic array minimizes the use of bends in layout shapes toeliminate unpredictable lithographic interactions. Specifically, priorto OPC or other RET processing, the dynamic array allows bends in thediffusion layer to enable control of device sizes, but does not allowbends in layers above the diffusion layer. The layout features in eachlayer above the diffusion layer are linear in shape, e.g., FIG. 3C, anddisposed in a parallel relationship with respect to each other. Thelinear shapes and parallel positioning of layout features areimplemented in each stack layer of the dynamic array wherepredictability of constructive light interference is necessary to ensuremanufacturability. In one embodiment, the linear shapes and parallelpositioning of layout features are implemented in the dynamic array ineach layer above diffusion through metal 2. Above metal 2, the layoutfeatures may be of sufficient size and shape that constructive lightinterference is not required to ensure manufacturability. However, thepresence of constructive light interference in patterning layoutfeatures above metal 2 may be beneficial.

An exemplary buildup of dynamic array layers from diffusion throughmetal 2 are described with respect to FIGS. 4 through 14. It should beappreciated that the dynamic array described with respect to FIGS. 4through 14 is provided by way of example only, and is not intended toconvey limitations of the dynamic array architecture. The dynamic arraycan be used in accordance with the principles presented herein to defineessentially any integrated circuit design.

FIG. 4 is an illustration showing a diffusion layer layout of anexemplary dynamic array, in accordance with one embodiment of thepresent invention. The diffusion layer of FIG. 4 shows a p-diffusionregion 401 and an n-diffusion region 403. While the diffusion regionsare defined according to the underlying base grid, the diffusion regionsare not subject to the linear-shaped feature restrictions associatedwith the layers above the diffusion layer. The diffusion regions 401 and403 include diffusion squares 405 defined where diffusion contacts willbe located. The diffusion regions 401 and 403 do not include extraneousjogs or corners, thus improving the use of lithographic resolution andenabling more accurate device extraction. Additionally, n+ mask regions(412 and 416) and p+ mask regions (410 and 414) are defined asrectangles on the (x), (y) grid with no extraneous jogs or notches. Thisstyle permits use of larger diffusion regions, eliminates need forOPC/RET, and enables use of lower resolution and lower cost lithographicsystems, e.g., line illumination at 365 nm. It should be appreciatedthat the n+ mask region 416 and the p+ mask region 410, as depicted inFIG. 4, are for an embodiment that does not employ well-biasing. In analternative embodiment where well-biasing is to be used, the n+ maskregion 416 shown in FIG. 4 will actually be defined as a p+ mask region.Also, in this alternative embodiment, the p+ mask region 410 shown inFIG. 4 will actually be defined as a n+ mask region.

FIG. 5 is an illustration showing a gate electrode layer and a diffusioncontact layer above and adjacent to the diffusion layer of FIG. 4, inaccordance with one embodiment of the present invention. As thoseskilled in the CMOS arts will appreciate, the gate electrode features501 define the transistor gates. The gate electrode features 501 aredefined as linear shaped features extending in a parallel relationshipacross the dynamic array in the second reference direction (y). In oneembodiment, the gate electrode features 501 are defined to have a commonwidth. However, in another embodiment, one or more of the gate electrodefeatures can be defined to have a different width. For example, FIG. 5shows a gate electrode features 501A that has a larger width relative tothe other gate electrode features 501. The pitch (center-to-centerspacing) of the gate electrode features 501 is minimized while ensuringoptimization of lithographic reinforcement, i.e., resonant imaging,provided by neighboring gate electrode features 501. For discussionpurposes, gate electrode features 501 extending across the dynamic arrayin a given line are referred to as a gate electrode track.

The gate electrode features 501 form n-channel and p-channel transistorsas they cross the diffusion regions 403 and 401, respectively. Optimalgate electrode feature 501 printing is achieved by drawing gateelectrode features 501 at every grid location, even though no diffusionregion may be present at some grid locations. Also, long continuous gateelectrode features 501 tend to improve line end shortening effects atthe ends of gate electrode features within the interior of the dynamicarray. Additionally, gate electrode printing is significantly improvedwhen all bends are removed from the gate electrode features 501.

Each of the gate electrode tracks may be interrupted, i.e., broken, anynumber of times in linearly traversing across the dynamic array in orderto provide required electrical connectivity for a particular logicfunction to be implemented. When a given gate electrode track isrequired to be interrupted, the separation between ends of the gateelectrode track segments at the point of interruption is minimized tothe extent possible taking into consideration the manufacturingcapability and electrical effects. In one embodiment, optimalmanufacturability is achieved when a common end-to-end spacing is usedbetween features within a particular layer.

Minimizing the separation between ends of the gate electrode tracksegments at the points of interruption serves to maximize thelithographic reinforcement, and uniformity thereof, provided fromneighboring gate electrode tracks. Also, in one embodiment, if adjacentgate electrode tracks need to be interrupted, the interruptions of theadjacent gate electrode tracks are made such that the respective pointsof interruption are offset from each other so as to avoid, to the extentpossible, an occurrence of neighboring points of interruption. Morespecifically, points of interruption within adjacent gate electrodetracks are respectively positioned such that a line of sight does notexist through the points of interruption, wherein the line of sight isconsidered to extend perpendicularly to the direction in which the gateelectrode tracks extend over the substrate. Additionally, in oneembodiment, the gate electrodes may extend through the boundaries at thetop and bottom of the cells, i.e., the PMOS or NMOS cells. Thisembodiment would enable bridging of neighboring cells.

With further regard to FIG. 5, diffusion contacts 503 are defined ateach diffusion square 405 to enhance the printing of diffusion contactsvia resonant imaging. The diffusion squares 405 are present around everydiffusion contact 503 to enhance the printing of the power and groundconnection polygons at the diffusion contacts 503.

The gate electrode features 501 and diffusion contacts 503 share acommon grid spacing. More specifically, the gate electrode feature 501placement is offset by one-half the grid spacing relative to thediffusion contacts 503. For example, if the gate electrode features 501and diffusion contact 503 grid spacing is 0.36 μm, then the diffusioncontacts are placed such that the x-coordinate of their center falls onan integer multiple of 0.36 μm, while the x-coordinate of the center ofeach gate electrode feature 501 minus 0.18 μm should be an integermultiple of 0.36 μm. In the present example, the x-coordinates arerepresented by the following:

-   -   Diffusion contact center x-coordinate=I*0.36 μm, where I is the        grid number;    -   Gate electrode feature center x-coordinate=0.18 μm+I*0.36 μm,        where I is the grid number.

The grid based system of the dynamic array ensures that all contacts(diffusion and gate electrode) will land on a horizontal grid that isequal to a multiple of one-half of the diffusion contact grid and avertical grid that is set by the metal 1 pitch. In the example above,the gate electrode feature and diffusion contact grid is 0.36 p.m. Thediffusion contacts and gate electrode contacts will land on a horizontalgrid that is a multiple of 0.18 μm. Also, the vertical grid for 90 nmprocess technologies is about 0.24 μm.

FIG. 6 is an illustration showing a gate electrode contact layer definedabove and adjacent to the gate electrode layer of FIG. 5, in accordancewith one embodiment of the present invention. In the gate electrodecontact layer, gate electrode contacts 601 are drawn to enableconnection of the gate electrode features 501 to the overlying metalconduction lines. In general, design rules will dictate the optimumplacement of the gate electrode contacts 601. In one embodiment, thegate electrode contacts are drawn on top of the transistor endcapregions. This embodiment minimizes white space in the dynamic array whendesign rules specify long transistor endcaps. In some processtechnologies white space may be minimized by placing a number of gateelectrode contacts for a cell in the center of the cell. Also, it shouldbe appreciated that in the present invention, the gate electrode contact601 is oversized in the direction perpendicular to the gate electrodefeature 501 to ensure overlap between the gate electrode contact 601 andthe gate electrode feature 501.

FIG. 7A is an illustration showing a traditional approach for makingcontact to a gate electrode, e.g., polysilicon feature. In thetraditional configuration of FIG. 7A, enlarged rectangular gateelectrode region 707 is defined where a gate electrode contact 709 is tobe located. The enlarged rectangular gate electrode region 707introduces a bend of distance 705 in the gate electrode. The bendassociated with the enlarged rectangular gate electrode region 707 setsup undesirable light interactions and distorts the gate electrode line711. Distortion of the gate electrode line 711 is especially problematicwhen the gate electrode width is about the same as a transistor length.

FIG. 7B is an illustration showing a gate electrode contact 601, e.g.,polysilicon contact, defined in accordance with one embodiment of thepresent invention. The gate electrode contact 601 is drawn to overlapthe edges of the gate electrode feature 501, and extend in a directionsubstantially perpendicular to the gate electrode feature 501. In oneembodiment, the gate electrode contact 601 is drawn such that thevertical dimension 703 is same as the vertical dimension used for thediffusion contacts 503. For example, if the diffusion contact 503opening is specified to be 0.12 μm square then the vertical dimension ofthe gate electrode contact 601 is drawn at 0.12 μm. However, in otherembodiments, the gate electrode contact 601 can be drawn such that thevertical dimension 703 is different from the vertical dimension used forthe diffusion contacts 503.

In one embodiment, the gate electrode contact 601 extension 701 beyondthe gate electrode feature 501 is set such that maximum overlap isachieved between the gate electrode contact 601 and the gate electrodefeature 501. The extension 701 is defined to accommodate line endshortening of the gate electrode contact 601, and misalignment betweenthe gate electrode contact layer and gate electrode feature layer. Thelength of the gate electrode contact 601 is defined to ensure maximumsurface area contact between the gate electrode contact 601 and the gateelectrode feature 501, wherein the maximum surface area contact isdefined by the width of the gate electrode feature 501.

FIG. 8A is an illustration showing a metal 1 layer defined above thegate electrode contact layer of FIG. 6, in accordance with oneembodiment of the present invention. The metal 1 layer includes a numberof metal 1 tracks 801-821 defined to include linear shaped featuresextending in a parallel relationship across the dynamic array. The metal1 tracks 801-821 extend in a direction substantially perpendicular tothe gate electrode features 501 in the underlying gate electrode layerof FIG. 5. Thus, in the present example, the metal 1 tracks 801-821extend linearly across the dynamic array in the first referencedirection (x). The pitch (center-to-center spacing) of the metal 1tracks 801-821 is minimized while ensuring optimization of lithographicreinforcement, i.e., resonant imaging, provided by neighboring metal 1tracks 801-821. For example, in one embodiment, the metal 1 tracks801-821 are centered on a vertical grid of about 0.24 for a 90 nmprocess technology.

Each of the metal 1 tracks 801-821 may be interrupted, i.e., broken, anynumber of times in linearly traversing across the dynamic array in orderto provide required electrical connectivity for a particular logicfunction to be implemented. When a given metal 1 track 801-821 isrequired to be interrupted, the separation between ends of the metal 1track segments at the point of interruption is minimized to the extentpossible taking into consideration manufacturing capability andelectrical effects. Minimizing the separation between ends of the metal1 track segments at the points of interruption serves to maximize thelithographic reinforcement, and uniformity thereof, provided fromneighboring metal 1 tracks. Also, in one embodiment, if adjacent metal 1tracks need to be interrupted, the interruptions of the adjacent metal 1tracks are made such that the respective points of interruption areoffset from each other so as to avoid, to the extent possible, anoccurrence of neighboring points of interruption. More specifically,points of interruption within adjacent metal 1 tracks are respectivelypositioned such that a line of sight does not exist through the pointsof interruption, wherein the line of sight is considered to extendperpendicularly to the direction in which the metal 1 tracks extend overthe substrate.

In the example of FIG. 8A, the metal 1 track 801 is connected to theground supply, and the metal 1 track 821 is connected to the powersupply voltage. In the embodiment of FIG. 8A, the widths of the metal 1tracks 801 and 821 are the same as the other metal 1 tracks 803-819.However, in another embodiment, the widths of metal 1 tracks 801 and 821are larger than the widths of the other metal 1 tracks 803-819. FIG. 8Bis an illustration showing the metal 1 layer of FIG. 8A with largertrack widths for the metal 1 ground and power tracks (801A and 821A),relative to the other metal 1 tracks 803-819.

The metal 1 track pattern is optimally configured to optimize the use of“white space” (space not occupied by transistors). The example of FIG.8A includes the two shared metal 1 power tracks 801 and 821, and ninemetal 1 signal tracks 803-819. Metal 1 tracks 803, 809, 811, and 819 aredefined as gate electrode contact tracks in order to minimize whitespace. Metal 1 tracks 805 and 807 are defined to connect to n-channeltransistor source and drains. Metal 1 tracks 813, 815, and 817 aredefined to connect to p-channel source and drains. Also, any of the ninemetal 1 signal tracks 803-819 can be used as a feed through if noconnection is required. For example, metal 1 tracks 813 and 815 areconfigured as feed through connections.

FIG. 9 is an illustration showing a via 1 layer defined above andadjacent to the metal 1 layer of FIG. 8A, in accordance with oneembodiment of the present invention. Vias 901 are defined in the via 1layer to enable connection of the metal 1 tracks 801-821 to higher levelconduction lines.

FIG. 10 is an illustration showing a metal 2 layer defined above andadjacent to the via 1 layer of FIG. 9, in accordance with one embodimentof the present invention. The metal 2 layer includes a number of metal 2tracks 1001 defined as linear shaped features extending in a parallelrelationship across the dynamic array. The metal 2 tracks 1001 extend ina direction substantially perpendicular to the metal 1 tracks 801-821 inthe underlying metal 1 layer of FIG. 8A, and in a directionsubstantially parallel to the gate electrode tracks 501 in theunderlying gate electrode layer of FIG. 5. Thus, in the present example,the metal 2 tracks 1001 extend linearly across the dynamic array in thesecond reference direction (y).

The pitch (center-to-center spacing) of the metal 2 tracks 1001 isminimized while ensuring optimization of lithographic reinforcement,i.e., resonant imaging, provided by neighboring metal 2 tracks. Itshould be appreciated that regularity can be maintained on higher levelinterconnect layers in the same manner as implemented in the gateelectrode and metal 1 layers. In one embodiment, the gate electrodefeature 501 pitch and the metal 2 track pitch is the same. In anotherembodiment, the contacted gate electrode pitch (e.g.,polysilicon-to-polysilicon space with a diffusion contact in between) isgreater than the metal 2 track pitch. In this embodiment, the metal 2track pitch is optimally set to be ⅔ or ¾ of the contacted gateelectrode pitch. Thus, in this embodiment, the gate electrode track andmetal 2 track align at every two gate electrode track pitches and everythree metal 2 track pitches. For example, in a 90 nm process technology,the optimum contacted gate electrode track pitch is 0.36 μm, and theoptimum metal 2 track pitch is 0.24 μm. In another embodiment, the gateelectrode track and the metal 2 track align at every three gateelectrode pitches and every four metal 2 pitches. For example, in a 90nm process technology, the optimum contacted gate electrode track pitchis 0.36 μm, and the optimum metal 2 track pitch is 0.27 μm.

Each of the metal 2 tracks 1001 may be interrupted, i.e., broken, anynumber of times in linearly traversing across the dynamic array in orderto provide required electrical connectivity for a particular logicfunction to be implemented. When a given metal 2 track 1001 is requiredto be interrupted, the separation between ends of the metal 2 tracksegments at the point of interruption is minimized to the extentpossible taking into consideration manufacturing and electrical effects.Minimizing the separation between ends of the metal 2 track segments atthe points of interruption serves to maximize the lithographicreinforcement, and uniformity thereof, provided from neighboring metal 2tracks. Also, in one embodiment, if adjacent metal 2 tracks need to beinterrupted, the interruptions of the adjacent metal 2 tracks are madesuch that the respective points of interruption are offset from eachother so as to avoid, to the extent possible, an occurrence ofneighboring points of interruption. More specifically, points ofinterruption within adjacent metal 2 tracks are respectively positionedsuch that a line of sight does not exist through the points ofinterruption, wherein the line of sight is considered to extendperpendicularly to the direction in which the metal 2 tracks extend overthe substrate.

As discussed above, the conduction lines in a given metal layer abovethe gate electrode layer may traverse the dynamic array in a directioncoincident with either the first reference direction (x) or the secondreference direction (y). It should be further appreciated that theconduction lines in a given metal layer above the gate electrode layermay traverse the dynamic array in a diagonal direction relative to thefirst and second reference directions (x) and (y). FIG. 11 is anillustration showing conductor tracks 1101 traversing the dynamic arrayin a first diagonal direction relative to the first and second referencedirections (x) and (y), in accordance with one embodiment of the presentinvention. FIG. 12 is an illustration showing conductor tracks 1201traversing the dynamic array in a second diagonal direction relative tothe first and second reference directions (x) and (y), in accordancewith one embodiment of the present invention.

As with the metal 1 and metal 2 tracks discussed above, the diagonaltraversing conductor tracks 1101 and 1201 of FIGS. 11 and 12 may beinterrupted, i.e., broken, any number of times in linearly traversingacross the dynamic array in order to provide required electricalconnectivity for a particular logic function to be implemented. When agiven diagonal traversing conductor track is required to be interrupted,the separation between ends of the diagonal conductor track at the pointof interruption is minimized to the extent possible taking intoconsideration manufacturing and electrical effects. Minimizing theseparation between ends of the diagonal conductor track at the points ofinterruption serves to maximize the lithographic reinforcement, anduniformity thereof, provided from neighboring diagonal conductor tracks.

An optimal layout density within the dynamic array is achieved byimplementing the following design rules:

at least two metal 1 tracks be provided across the n-channel devicearea;

at least two metal 1 tracks be provided across the p-channel devicearea;

at least two gate electrode tracks be provided for the n-channel device;and

at least two gate electrode tracks be provided for the p-channel device.

Contacts and vias are becoming the most difficult mask from alithographic point of view. This is because the contacts and vias aregetting smaller, more closely spaced, and are randomly distributed. Thespacing and density of the cuts (contact or vias) makes it extremelydifficult to reliably print the shapes. For example, cut shapes may beprinted improperly due to destructive interference patterns fromneighboring shapes or lack of energy on lone shapes. If a cut isproperly printed, the manufacturing yield of the associated contact orvia is extremely high. Sub-resolution contacts can be provided toreinforce the exposure of the actual contacts, so long as thesub-resolution contacts do not resolve. Also, the sub-resolutioncontacts can be of any shape so long as they are smaller than theresolution capability of the lithographic process.

FIG. 13A is an illustration showing an example of a sub-resolutioncontact layout used to lithographically reinforce diffusion contacts andgate electrode contacts, in accordance with one embodiment of thepresent invention. Sub-resolution contacts 1301 are drawn such that theyare below the resolution of the lithographic system and will not beprinted. The function of the sub-resolution contacts 1301 is to increasethe light energy at the desired contact locations, e.g., 503, 601,through resonant imaging. In one embodiment, sub-resolution contacts1301 are placed on a grid such that both gate electrode contacts 601 anddiffusion contacts 503 are lithographically reinforced. For example,sub-resolution contacts 1301 are placed on a grid that is equal toone-half the diffusion contact 503 grid spacing to positively impactboth gate electrode contacts 601 and diffusion contacts 503. In oneembodiment, a vertical spacing of the sub-resolution contacts 1301follows the vertical spacing of the gate electrode contacts 601 anddiffusion contacts 503.

Grid location 1303 in FIG. 13A denotes a location between adjacent gateelectrode contacts 601. Depending upon the lithographic parameters inthe manufacturing process, it is possible that a sub-resolution contact1301 at this grid location would create an undesirable bridge betweenthe two adjacent gate electrode contacts 601. If bridging is likely tooccur, a sub-resolution contact 1301 at location 1303 can be omitted.Although FIG. 13A shows an embodiment where sub-resolution contacts areplaced adjacent to actual features to be resolved and not elsewhere, itshould be understood that another embodiment may place a sub-resolutioncontact at each available grid location so as to fill the grid.

FIG. 13B is an illustration showing the sub-resolution contact layout ofFIG. 13A with sub-resolution contacts defined to fill the grid to theextent possible, in accordance with one embodiment of the presentinvention. It should be appreciated that while the embodiment of FIG.13B fills the grid to the extent possible with sub-resolution contacts,placement of sub-resolution contacts is avoided at locations that wouldpotentially cause undesirable bridging between adjacent fully resolvedfeatures.

FIG. 13C is an illustration showing an example of a sub-resolutioncontact layout utilizing various shaped sub-resolution contacts, inaccordance with one embodiment of the present invention. Alternativesub-resolution contact shapes can be utilized so long as thesub-resolution contacts are below the resolution capability of themanufacturing process. FIG. 13C shows the use of “X-shaped”sub-resolution contacts 1305 to focus light energy at the corners of theadjacent contacts. In one embodiment, the ends of the X-shapedsub-resolution contact 1305 are extended to further enhance thedeposition of light energy at the corners of the adjacent contacts.

FIG. 13D is an illustration showing an exemplary implementation ofalternate phase shift masking (APSM) with sub-resolution contacts, inaccordance with one embodiment of the present invention. As in FIG. 13A,sub-resolution contacts are utilized to lithographically reinforcediffusion contacts 503 and gate electrode contacts 601. APSM is used toimprove resolution when neighboring shapes create destructiveinterference patterns. The APSM technique modifies the mask so that thephase of light traveling through the mask on neighboring shapes is 180degrees out of phase. This phase shift serves to remove destructiveinterference and allowing for greater contact density. By way ofexample, contacts in FIG. 13D marked with a plus “+” sign representcontacts exposed with light waves of a first phase while contacts markedwith a minus sign “−” represent contacts exposed with light waves thatare shifted in phase by 180 degrees relative to the first phase used forthe “+” sign contacts. It should be appreciated that the APSM techniqueis utilized to ensure that adjacent contacts are separated from eachother.

As feature sizes decrease, semiconductor dies are capable of includingmore gates. As more gates are included, however, the density of theinterconnect layers begins to dictate the die size. This increasingdemand on the interconnect layers drives higher levels of interconnectlayers. However, the stacking of interconnect layers is limited in partby the topology of the underlying layers. For example, as interconnectlayers are built up, islands, ridges, and troughs can occur. Theseislands, ridges, and troughs can cause breaks in the interconnect linesthat cross them

To mitigate these islands and troughs, the semiconductor manufacturingprocess utilizes a chemical mechanical polishing (CMP) procedure tomechanically and chemically polish the surface of the semiconductorwafer such that each subsequent interconnect layer is deposited on asubstantially flat surface. Like the photolithography process thequality of the CMP process is layout pattern dependent. Specifically, anuneven distribution of a layout features across a die or a wafer cancause too much material to be removed in some places and not enoughmaterial to be removed in other places, thus causing variations in theinterconnect thickness and unacceptable variations in the capacitanceand resistance of the interconnect layer. The capacitance and resistancevariation within the interconnect layer may alter the timing of acritical net causing design failure.

The CMP process requires that dummy fill be added in the areas withoutinterconnect shapes so that a substantially uniform wafer topology isprovided to avoid dishing and improve center-to-edge uniformity.Traditionally, dummy fill is placed post-design. Thus, in thetraditional approach the designer is not aware of the dummy fillcharacteristics. Consequently, the dummy fill placed post-design mayadversely influence the design performance in a manner that has not beenevaluated by the designer. Also, because the conventional topology priorto the dummy fill is unconstrained, i.e., non-uniform, the post-designdummy fill will not be uniform and predictable. Therefore, in theconventional process, the capacitive coupling between the dummy fillregions and the neighboring active nets cannot be predicted by thedesigner.

As previously discussed, the dynamic array disclosed herein providesoptimal regularity by maximally filling all interconnect tracks fromgate electrode layer upward. If multiple nets are required in a singleinterconnect track, the interconnect track is split with a minimallyspaced gap. For example, track 809 representing the metal 1 conductionline in FIG. 8A represents three separate nets in the same track, whereeach net corresponds to a particular track segment. More specifically,there are two poly contact nets and a floating net to fill the trackwith minimal spacing between the track segments. The substantiallycomplete filling of tracks maintains the regular pattern that createsresonant images across the dynamic array. Also, the regular architectureof the dynamic array with maximally filled interconnect tracks ensuresthat the dummy fill is placed in a uniform manner across the die.Therefore, the regular architecture of the dynamic array assists the CMPprocess to produce substantially uniform, results across the die/wafer.Also, the regular gate pattern of the dynamic array assists with gateetching uniformity (microloading). Additionally, the regulararchitecture of the dynamic array combined with the maximally filledinterconnect tracks allows the designer to analyze the capacitivecoupling effects associated with the maximally filled tracks during thedesign phase and prior to fabrication.

Because the dynamic array sets the size and spacing of the linearlyshaped features, i.e., tracks and contacts, in each mask layer, thedesign of the dynamic array can be optimized for the maximum capabilityof the manufacturing equipment and processes. That is to say, becausethe dynamic array is restricted to the regular architecture for eachlayer above diffusion, the manufacturer is capable of optimizing themanufacturing process for the specific characteristics of the regulararchitecture. It should be appreciated that with the dynamic array, themanufacturer does not have to be concerned with accommodating themanufacture of a widely varying set of arbitrarily-shaped layoutfeatures as is present in conventional unconstrained layouts.

An example of how the capability of manufacturing equipment can beoptimized is provided as follows. Consider that a 90 nm process has ametal 2 pitch of 280 nm. This metal 2 pitch of 280 nm is not set by themaximum capability of equipment. Rather, this metal 2 pitch of 280 nm isset by the lithography of the vias. With the via lithography issuesremoved, the maximum capability of the equipment allows for a metal 2pitch of about 220 nm. Thus, the design rules for metal 2 pitch includeabout 25% margin to account for the light interaction unpredictabilityin the via lithography.

The regular architecture implemented within the dynamic array allows thelight interaction unpredictability in the via lithography to be removed,thus allowing for a reduction in the metal 2 pitch margin. Such areduction in the metal 2 pitch margin allows for a more dense design,i.e., allows for optimization of chip area utilization. Additionally,with the restricted, i.e., regular, topology afforded by the dynamicarray, the margin in the design rules can be reduced. Moreover, not onlycan the excess margin beyond the capability of the process be reduced,the restricted topology afforded by the dynamic array also allows thenumber of required design rules to be substantially reduced. Forexample, a typical design rule set for an unconstrained topology couldhave more than 600 design rules. A design rule set for use with thedynamic array may have about 45 design rules. Therefore, the effortrequired to analyze and verify the design against the design rules isdecreased by more than a factor of ten with the restricted topology ofthe dynamic array.

When dealing with line end-to-line end gaps (i.e., tracksegment-to-track segment gaps) in a given track of a mask layer in thedynamic array, a limited number of light interactions exist. Thislimited number of light interactions can be identified, predicted, andaccurately compensated for ahead of time, dramatically reducing orcompletely eliminating the requirement for OPC/RET. The compensation forlight interactions at line end-to-line end gaps represents alithographic modification of the as-drawn feature, as opposed to acorrection based on modeling of interactions, e.g., OPC/RET, associatedwith the as-drawn feature.

Also, with the dynamic array, changes to the as-drawn layout are onlymade where needed. In contrast, OPC is performed over an entire layoutin a conventional design flow. In one embodiment, a correction model canbe implemented as part of the layout generation for the dynamic array.For example, due to the limited number of possible line end gapinteractions, a router can be programmed to insert a line break havingcharacteristics defined as a function of its surroundings, i.e., as afunction of its particular line end gap light interactions. It should befurther appreciated that the regular architecture of the dynamic arrayallows the line ends to be adjusted by changing vertices rather than byadding vertices. Thus, in contrast with unconstrained topologies thatrely on the OPC process, the dynamic array significantly reduces thecost and risk of mask production. Also, because the line end gapinteractions in the dynamic array can be accurately predicted in thedesign phase, compensation for the predicted line end gap interactionsduring the design phase does not increase risk of design failure.

In conventional unconstrained topologies, designers are required to haveknowledge of the physics associated with the manufacturing process dueto the presence of design dependent failures. With the grid-based systemof the dynamic array as disclosed herein, the logical design can beseparated from the physical design. More specifically, with the regulararchitecture of the dynamic array, the limited number of lightinteractions to be evaluated within the dynamic array, and the designindependent nature of the dynamic array, designs can be representedusing a grid point based netlist, as opposed to a physical netlist.

With the dynamic array, the design is not required to be represented interms of physical information. Rather, the design can be represented asa symbolic layout. Thus, the designer can represent the design from apure logic perspective without having to represent physicalcharacteristics, e.g., sizes, of the design. It should be understoodthat the grid-based netlist, when translated to physical, matches theoptimum design rules exactly for the dynamic array platform. When thegrid-based dynamic array moves to a new technology, e.g., smallertechnology, a grid-based netlist can be moved directly to the newtechnology because there is no physical data in the designrepresentation. In one embodiment, the grid-based dynamic array systemincludes a rules database, a grid-based (symbolic) netlist, and thedynamic array architecture.

It should be appreciated that the grid-based dynamic array eliminatestopology related failures associated with conventional unconstrainedarchitectures. Also, because the manufacturability of the grid-baseddynamic array is design independent, the yield of the design implementedon the dynamic array is independent of the design. Therefore, becausethe validity and yield of the dynamic array is preverified, thegrid-based netlist can be implemented on the dynamic array withpreverified yield performance.

FIG. 14 is an illustration showing a semiconductor chip structure 1400,in accordance with one embodiment of the present invention. Thesemiconductor chip structure 1400 represents an exemplary portion of asemiconductor chip, including a diffusion region 1401 having a number ofconductive lines 1403A-1403G defined thereover. The diffusion region1401 is defined in a substrate 1405, to define an active region for atleast one transistor device. The diffusion region 1401 can be defined tocover an area of arbitrary shape relative to the substrate 1405 surface.

The conductive lines 1403A-1403G are arranged to extend over thesubstrate 1405 in a common direction 1407. It should also be appreciatedthat each of the number of conductive lines 1403A-1403G are restrictedto extending over the diffusion region 1401 in the common direction1407. In one embodiment, the conductive lines 1403A-1403G definedimmediately over the substrate 1405 are polysilicon lines. In oneembodiment, each of the conductive lines 1403A-1403G is defined to haveessentially the same width 1409 in a direction perpendicular to thecommon direction 1407 of extension. In another embodiment, some of theconductive lines 1403A-1403G are defined to have different widthsrelative to the other conductive lines. However, regardless of the widthof the conductive lines 1403A-1403G, each of the conductive lines1403A-1403G is spaced apart from adjacent conductive lines according toessentially the same center-to-center pitch 1411.

As shown in FIG. 14, some of the conductive lines (1403B-1403E) extendover the diffusion region 1401, and other conductive lines (1403A,1403F, 1403G) extend over non-diffusion portions the substrate 1405. Itshould be appreciated that the conductive lines 1403A-1403G maintaintheir width 1409 and pitch 1411 regardless of whether they are definedover diffusion region 1401 or not. Also, it should be appreciated thatthe conductive lines 1403A-1403G maintain essentially the same length1413 regardless of whether they are defined over diffusion region 1401or not, thereby maximizing lithographic reinforcement between theconductive lines 1403A-1403G across the substrate. In this manner, someof the conductive lines, e.g., 1403D, defined over the diffusion region1401 include a necessary active portion 1415, and one or more uniformityextending portions 1417.

It should be appreciated that the semiconductor chip structure 1400represents a portion of the dynamic array described above with respectto FIGS. 2-13D. Therefore, it should be understood that the uniformityextending portions 1417 of the conductive lines (1403B-1403E) arepresent to provide lithographic reinforcement of neighboring conductivelines 1403A-1403G. Also, although they may not be required for circuitoperation, each of conductive lines 1403A, 1403F, and 1403G are presentto provide lithographic reinforcement of neighboring conductive lines1403A-1403G.

The concept of the necessary active portion 1415 and the uniformityextending portions 1417 also applies to higher level interconnectlayers. As previously described with regard to the dynamic arrayarchitecture, adjacent interconnect layers traverse over the substratein transverse directions, e.g., perpendicular or diagonal directions, toenable routing/connectivity required by the logic device implementedwithin the dynamic array. As with the conductive lines 1403A-1403G, eachof the conductive lines within an interconnect layer may include arequired portion (necessary active portion) to enable requiredrouting/connectivity, and a non-required portion (uniformity extendingportion) to provide lithographic reinforcement to neighboring conductivelines. Also, as with the conductive lines 1403A-1403G, the conductivelines within an interconnect layer extend in a common direction over thesubstrate, have essentially the same width, and are spaced apart fromeach other according to an essentially constant pitch.

In one embodiment, conductive lines within an interconnect layer followessentially the same ratio between line width and line spacing. Forexample, at 90 nm the metal 4 pitch is 280 nm with a line width and linespacing equal to 140 nm. Larger conductive lines can be printed on alarger line pitch if the line width is equal to the line spacing.

FIG. 15 shows an example layout architecture defined in accordance withone embodiment of the present invention. The layout architecture followsa grid pattern and is based upon a horizontal grid and a vertical grid.The horizontal grid is set by the poly gate pitch. The vertical pitch isset by the metal 1/metal 3 pitch. All of the rectangular shapes shouldbe centered on a grid point. The layout architecture minimizes the useof bends to eliminate unpredictable lithographic interactions. Bends areallowed on the diffusion layer to control transistor device sizes. Otherlayers should be rectangular in shape and fixed in one dimension.

The invention described herein can be embodied as computer readable codeon a computer readable medium. The computer readable medium is any datastorage device that can store data which can be thereafter be read by acomputer system. Examples of the computer readable medium include harddrives, network attached storage (NAS), read-only memory, random-accessmemory, CD-ROMs, CD-Rs, CD-RWs, magnetic tapes, and other optical andnon-optical data storage devices. The computer readable medium can alsobe distributed over a network coupled computer systems so that thecomputer readable code is stored and executed in a distributed fashion.Additionally, a graphical user interface (GUI) implemented as computerreadable code on a computer readable medium can be developed to providea user interface for performing any embodiment of the present invention.

While this invention has been described in terms of several embodiments,it will be appreciated that those skilled in the art upon reading thepreceding specifications and studying the drawings will realize variousalterations, additions, permutations and equivalents thereof. Therefore,it is intended that the present invention includes all such alterations,additions, permutations, and equivalents as fall within the true spiritand scope of the invention.

What is claimed is:
 1. An integrated circuit, comprising: a first gateelectrode feature of a first gate electrode track, wherein the firstgate electrode feature of the first gate electrode track forms a firstn-channel transistor as it crosses an n-diffusion region; a second gateelectrode feature of the first gate electrode track, wherein the secondgate electrode feature of the first gate electrode track forms a firstp-channel transistor as it crosses a p-diffusion region, wherein thefirst and second gate electrode features of the first gate electrodetrack are separated by a first end-to-end spacing; a first gateelectrode feature of a second gate electrode track, wherein the firstgate electrode feature of the second gate electrode track forms a secondn-channel transistor as it crosses the n-diffusion region; and a secondgate electrode feature of the second gate electrode track, wherein thesecond gate electrode feature of the second gate electrode track forms asecond p-channel transistor as it crosses the p-diffusion region,wherein the first and second gate electrode features of the second gateelectrode track are separated by a second end-to-end spacing that isoffset from the first end-to-end spacing such that a line of sightperpendicular to the first and second gate electrode tracks does notexist through the first and second end-to-end spacings.